Enemy AI Problem: Dancing?

Edit: The actual movement of the enemy has now been fixed with this script update. Now, the buggy, dance-like rotation needs to be fixed. Suggestions?

I have created an "AI" script for a third person game that is somewhat functional, but is buggy. I want the enemy to rotate to "look" at the player, go up to the player when the player has come within a certain distance, and attack the player at a certain distance. The enemy rotates properly at a distance, but moves crazily when closer. The movement is like a quick, erotic, jumpy dance that circles the player... It looks cool, but it isn't what I want.

Here is the AI script:

 //    #pragma strict
 
 // Set variables related to movement and individual states.
 
 var idleTime : float = 3.1;
 var marManMoveSpeed : float;
 var marManRotateSpeed : float;
 var gravity : float;
 var attackTarget : Transform;
 var chaseDistance : float;
 var attackDistance : float;
 private var moveDirection : Vector3 = Vector3.zero;
 private var wait : boolean = false;
 
 // Set variables for the states.
 private var idle : int = 0;
 private var walk : int = 1;
 private var attack : int = 2;
 private var status : int = idle;
 var controller : CharacterController;
 controller = GetComponent(CharacterController);
 
 
 function Update(){
     var controller : CharacterController = GetComponent(CharacterController);
     moveDirection.x = 0;
     moveDirection.z = 0;

     var aggro : float = Vector3.Distance(attackTarget.position,transform.position);    
     //print(aggro);    
     //Define what causes the states.
 
     if (aggro < chaseDistance && aggro > attackDistance){
         status = walk;
     }
 
     else if(aggro < attackDistance * 0.8){
         status = attack;
     }
 
     else if(aggro > chaseDistance){
 
         status = idle;
 
     }    
     
     
     
     //State what to do in each of the states.    
     if (controller.isGrounded){
         switch(status){
             case idle:
                 //Currently does nothing, but will hopefully have animation here.
                 break;
 
             case walk:
                 //Insert animation later.
                 //Rotation handled later in script.                
                 //Set the direction for movement.
                 moveDirection = Vector3(attackTarget.position.x - transform.position.x,0,attackTarget.position.z - transform.position.z);
                             moveDirection.Normalize();
                 break;
             case attack:
                 //Insert "attack" animation later. Required for end use.
                 //Rotation handled later in script.
                 break;
 
             default:
                 return;
         }
 
     }

     //Always apply gravity.    
     moveDirection[1] -= gravity * Time.deltaTime;
     
     Move();
 }
 
 
     function Move(){
         if(!wait){
             //Handle all movement in here.
             transform.LookAt(attackTarget);
             controller.Move(moveDirection * marManMoveSpeed * Time.deltaTime);
     }
 
     else{
     //Wait for assigned time and do nothing!
     Debug.LogWarning("Current status - waiting for "+idleTime);
         yield WaitForSeconds(idleTime);
         return;
         }
     }
     @script RequireComponent(CharacterController)

Here are the settings for this script in the inspector:

 Idle Time = 3.1
 Mar Man Move Speed = 5.291004
 Mar Man Rotate Speed = 360
 Gravity = 50
 Attack Target = Player (Transform)
 Chase Distance = 5
 Attack Distance = 1.75
 Controller = Enemy (Character Controller)